KR20110013368A - Absorbent articles capable of indicating the presence of urine - Google Patents

Abstract

According to one embodiment of the invention, a method of detecting urine is described. This method involves contacting urine with a substrate. The substrate comprises charged cellulose fibers to which the discoloration composition is immobilized, the discoloration composition comprising a pH indicator, a pH adjuster, and a wetting agent, wherein the pH indicator is configured to discolor upon contact with urine. The presence of urine is determined based on discoloration of the pH indicator.

Description

Absorption article which can indicate presence of urine {ABSORBENT ARTICLES CAPABLE OF INDICATING THE PRESENCE OF URINE}

Disposable absorbent articles, such as diapers, training pants, incontinence pads, and the like, are highly absorbent and efficiently attract moisture from the wearer, thereby reducing skin irritation caused by prolonged wet exposure. However, these articles are so absorbent that the wearer may not realize that they are urinating, especially for an immature child who is unable to recognize the meaning of the body sensations associated with urination. That is, the wearer cannot recognize his or her urination control failure or perceive that the article needs to be replaced. Furthermore, the parent or guardian cannot recognize that the absorbent article needs to be replaced.

Visual mechanisms are being used to indicate the wetting occurrence of absorbent articles. Many wet sensing techniques exist that utilize such visual mechanisms. For example, recent wet sensing techniques use highly charged porous nylon membranes to fix pH indicators that may discolor in the presence of urine. The discoloration contrast of highly charged porous nylon membranes is greater than that found in the prior art. However, despite its excellent sensing performance, nylon membranes can be very expensive.

Materials formed from cellulose fibers are more readily available and relatively inexpensive compared to nylon membranes. Cellulose fibers can be modified to have a high density surface charge and can also be used to make porous webs.

Thus, there is a need for cellulosic fibrous materials that can effectively utilize discoloration mechanisms similar to those found in nylon membranes to indicate the presence of urine. Absorbent articles comprising such materials would be particularly advantageous.

According to one embodiment of the invention, a method of detecting urine is described. This method involves contacting urine with a substrate. The substrate comprises charged cellulose fibers to which the discoloration composition is immobilized, the discoloration composition comprising a pH indicator, a pH adjuster, and a wetting agent, wherein the pH indicator is configured to discolor upon contact with urine. The presence of urine is determined based on discoloration of the pH indicator.

In another embodiment of the present invention, an absorbent article is described that can determine the presence of urine. The absorbent article includes a substantially liquid impermeable layer, a liquid permeable layer, an absorbent core positioned between the substantially liquid impermeable layer and the liquid permeable layer, and in fluid communication with the urine that is incorporated into the article and is generated by the article wearer. Positioned charged cellulose fibers. The discolored composition is fixed to the charged cellulose fibers, the discoloring composition comprising a pH indicator, a pH adjuster, and a wetting agent, and the indicator is configured to discolor upon contact with urine.

Other features and aspects of the present invention will be discussed in more detail below.

The complete and feasible disclosure, including the best mode for the skilled person, is described in more detail in the remainder of the specification with reference to the accompanying drawings.
1 is a perspective view of one embodiment of an absorbent article that may be used in the present invention.
Repeat use of reference characters in the present specification and drawings is intended to indicate the same or similar features or elements in the invention.

Reference will now be made in detail to various embodiments of the invention, and one or more examples thereof will be described. Each example is provided by way of explanation of the invention, not limitation of the invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment may be used in another embodiment to derive another embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

The present invention relates to a material formed from cellulose fibers which can schematically indicate the presence of urine. Fixed pH indicators are used with the material to accurately indicate the presence of urine. The poor performance of conventional cellulose fiber based substrates is believed to be the result of low indicator loading capacity and poor urine wetting. Some conventional materials do not fix the pH indicators resulting in diffusion leaching of such indicators. The present invention discloses a substrate formed from cellulose fibers treated with charged polymers, which substrate has an improved improved indicator loading capacity. In addition, the material of the present invention includes a discoloration composition having a pH indicator, a pH adjuster, and a wetting agent that provides improved urine wetting. The materials described herein can be produced at low cost while still exhibiting very good performance.

The present invention provides a simple, easy to use and cost effective approach for the rapid determination of the presence of urine. In addition, the materials described herein may be incorporated into absorbent articles such as diapers and incontinence pads to assist in the determination of urine presence.

Schematically speaking, the present invention describes a substrate comprising charged cellulose fibers coated with a discoloring composition for indicating the presence of urine. The substrate may be formed in such a way that urine can pass through it.

The substrate may be a porous web formed from natural materials such as polysaccharides such as cellulose materials such as paper and cellulose derivatives such as cellulose acetate and nitrocellulose. For example, the substrate may include fibers formed by various pulping processes, such as kraft pulp, sulfite pulp, thermochemical pulp, and the like. Pulp fibers include softwood fibers having an average fiber length of greater than 1 mm and in particular about 2 to 5 mm in length weighted average. Such softwood fibers include, but are not limited to, northern softwood, southern softwood, American cedar, cedar, poison wood, pine (e.g. southern pine), spruce (e.g. black spruce), combinations thereof, and the like. Does not. Exemplary commercial pulp fibers suitable for the present invention include those available under the trade name " Longlac-19 " from Kimberly-Clark Corporation.

Hardwood fibers such as eucalyptus, maple, birch, aspen and the like can also be used. In certain cases, eucalyptus fibers may be particularly desirable because the fibers are thin and not highly mobile. Also, if desired, secondary fibers obtained from recycled materials such as pulp fibers from raw materials such as newspapers, recycled cardboard, and office tissue can be used. Other natural fibers such as manila hemp, sabai grass, milkweed floss, pineapple leaves and the like can also be used in the present invention.

In addition, in some cases, synthetic fibers may be used in combination with the cellulose fibers described herein. Some suitable synthetic fibers include, but are not limited to, rayon fibers, ethylene vinyl alcohol copolymer fibers, polyolefin fibers, polyesters, and the like. As used herein, “synthetic fibers” refers to artificial polymer fibers that may include one or more polymers, each of which may have been produced from one or more monomers. The polymeric material in the synthetic fibers is independently thermoplastic, thermoset, elastomeric, not elastomeric, crimped, substantially crimped, colored, uncolored, filled with filler material, not filled, or It may be birefringent, circular cross section, multilobal or other non-circular cross section, or the like. Synthetic fibers can be made by any known technique. Synthetic fibers may be monocomponent fibers, such as filaments of polyester, polyolefins or other thermoplastics, or may be bicomponent or multicomponent fibers. When more than one polymer is present in a fiber, the polymers are blended, microscopic or macroscopically phase separated, present in side-by-side or sheath-core structures, or in the art Can be distributed in any manner known in the art.

It will be appreciated that any suitable web forming method may be contemplated for use in the present invention. The size and shape of the substrate may generally vary, as will be readily appreciated by those skilled in the art, and may also depend on the web formation method used. For example, the porous web may have a length of about 10 to about 100 millimeters, in some embodiments about 20 to about 80 millimeters, and in some embodiments, about 40 to about 60 millimeters. The width of the web may also range from about 0.5 to about 20 millimeters, in some embodiments from about 1 to about 15 millimeters, and in some embodiments, from about 2 to about 10 millimeters. The thickness of the web may be less than about 500 micrometers, in some embodiments less than about 250 micrometers, and in some embodiments less than about 150 micrometers. The size and shape of the substrate should be sufficient to show the discoloration occurring therein.

As discussed above, the fibers of the present invention may be treated with charged polymers before contacting the discoloration composition. For example, it has been found that wet and dry strength imparting agents can be advantageously used in connection with the present invention. As used herein, "wet strength imparting agent" refers to a material used to fix bonds between fibers in the wet state. Any material that will provide a tissue sheet with an average wet geometric tensile strength to dry geometric tensile strength ratio of greater than about 0.1 when added to the web is referred to as a wet strength imparting agent for the purposes of the present invention. Typically, such materials are referred to as permanent wet strength agents or "temporary" wet strength agents. To distinguish the permanent wet strength imparting agent from the temporary wet strength imparting agent, the permanent wet strength imparting agent can provide a web that maintains greater than 50% of its original wet strength after exposure to water for at least 5 minutes when incorporated into the web. It will be defined as a resin. Temporary wet strength impartants are those that show about 50% or less of the original wet strength after saturation with water for 5 minutes. Both classes of wet strength imparting agents can be applied to the materials of the present invention. When present, the amount of wet strength imparting agent added to the pulp fibers is at least about 0.1 dry weight percent, more specifically at least about 0.2 dry weight percent, even more specifically about 0.1 to about 3 dry weight, based on the dry weight of the fiber. May be%. Suggested treatment methods include, but are not limited to, saturation, spraying, slot dies, printing, foaming, and combinations and variations thereof.

Temporary wet strength imparting agents can be cationic or anionic. Such compounds include, but are not limited to, PAREZ ™ 631 NC and PAREZ® 725 temporary wet strength resins, which are cationic glyoxylated polyacrylamides available from Cytec Industries (West Patterson, NJ). Do not. Hercobond 1366, manufactured by Hercules, Inc., Wilmington, Delaware, USA, is also a commercially available cationic glyoxylated polyacrylamide that can be used according to the present invention. Further examples of temporary wet strength imparting agents include dialdehyde starches such as Cobond® 1000 from National Starch and Chemical Company and other aldehyde containing polymers known in the art.

Suitable permanent wet strength imparting agents include cationic oligomers or polymeric resins. Resin of polyamide-polyamine-epichlorohydrin type, for example KYMENE 557H sold by Hercules, Inc., Wilmington, Delaware, USA, or another resin sold under the name KYMENE is a permanent wet strength imparting agent. Widely used as. Other cationic resins include polyethyleneimine resins and aminoplast resins obtained by the reaction of formaldehyde with melamine or urea.

After treatment with the charged polymer, the discoloration composition of the present invention can be applied to the fibers using any known application technique. Preferably, after the color change composition is applied to the fibers, the fibers may be incorporated into the web or may be blended with other fibers to incorporate the web. Likewise, suggested treatment methods include, but are not limited to, saturation, spraying, slot die, printing, foaming, and combinations and variations thereof.

The discoloration composition of this invention contains a pH indicator. Various solvents can be used for solution formation of pH indicators, such as but not limited to water, acetonitrile, dimethyl sulfoxide (DMSO), ethyl alcohol, dimethylformamide (DMF), and other polar organic solvents. The amount of pH indicator in the solution may range from about 0.001 to about 100 milligrams per milliliter of solvent, and in some embodiments from about 0.1 to about 10 milligrams per milliliter of solvent. The pH indicator concentration can optionally be adjusted to provide the desired level of detection sensitivity.

In certain embodiments of the invention, a crosslinked network containing a pH indicator is formed on the substrate. Without wishing to be bound by theory, cross-linked networks may help the user securely fix the pH indicator to allow the user to more easily detect their discoloration during use. A crosslinked network may be referred to as "internal crosslinking" (ie, covalent bonds between functional groups in a single molecule) and / or "crosslinking" (ie, covalent bonds between different molecules, such as between two pH indicator molecules, or pH indicators). Covalent bonds between the molecule and the substrate surface). Crosslinking may be carried out through self-crosslinking of the indicator and / or through the introduction of a separate crosslinking agent. Suitable crosslinkers include, for example, polyglycidyl ethers such as ethylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether; Acrylamide; One or more hydrolyzable groups such as alkoxy groups (eg methoxy, ethoxy and propoxy); Alkoxyalkoxy groups such as methoxyethoxy, ethoxyethoxy and methoxypropoxy; Acyloxy groups such as acetoxy and octanoyloxy; Ketoxime groups (eg, dimethylketoxime, methylketoxime and methylethylketoxime); Alkenyloxy groups such as vinyloxy, isopropenyloxy and 1-ethyl-2-methylvinyloxy; Amino groups such as dimethylamino, diethylamino and butylamino; Aminoxy groups (eg, dimethylaminooxy and diethylaminooxy); And amide groups such as N-methylacetamide and N-ethylacetamide.

Any of a variety of different crosslinking mechanisms may be used in the present invention, for example, thermal initiation (eg, condensation reactions, addition reactions, etc.), electromagnetic radiation, and the like. Some suitable examples of electromagnetic radiation that can be used in the present invention include electron beam radiation, natural and artificial radioisotopes (e.g. α, β and γ rays), x-rays, neutron beams, positively charged beams, laser beams, ultraviolet rays Etc., but is not limited thereto. Electron beam radiation includes the production of accelerated electrons, for example by an electron beam device. Electron beam devices are generally well known in the art. For example, in one embodiment, an electron beam device can be used that is available under the name "Microbeam LV" from Energy Sciences, Inc., Woburn, Mass., USA. Other examples of suitable electron beam devices are described in US Pat. No. 5,003,178 (Livesay), 5,962,995 (Avnery), 6,407,492 (Avnery, et al.), Which are hereby incorporated by reference in their entirety for all purposes. Included for reference. The wavelength λ of the radiation is about 10 ^-14 depending on the different radiation types in the electromagnetic spectrum ^May vary from meters to about 10 ^-5 meters. For example, electron beam radiation has a wavelength λ of about 10 ⁻¹³ meters to about 10 ⁻⁹ meters. In addition to selecting a specific wavelength λ of the electromagnetic radiation, other parameters may be selected to adjust the degree of crosslinking. For example, the dose may range from about 0.1 Mrads to about 10 Mrads, in some embodiments from about 1 Mrads to about 5 Mrads.

The source of electromagnetic radiation can be any radiation source known to those skilled in the art. For example, excimer lamps or mercury lamps with D-bulbs can be used. Other specialty-doped lamps that emit radiation at fairly narrow emission peaks can be used with photoinitiators having an equivalent maximum absorption point. For example, the V-bulb available from Fusion Systems is another lamp suitable for use. In addition, specialty lamps with specific emission bands can be prepared for use with one or more specific photoinitiators.

In some embodiments, initiators may be used that enhance the function of the selected crosslinking technique. For example, in certain embodiments, thermal initiators such as azo, peroxide, persulfate, and redox initiators can be used. Representative examples of suitable thermal initiators include 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (isobutyronitrile), 2,2'-azobis-2-methyl Butyronitrile, 1,1'-azobis (1-cyclohexanecarbonitrile), 2,2'-azobis (methyl isobutyrate), 2,2'-azobis (2-amidinopropane) dihydrochloride Azo initiators such as 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile); Benzoyl peroxide, acetyl peroxide, lauroyl peroxide, decanoyl peroxide, dicetyl peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di (2-ethylhexyl) Peroxide initiators such as peroxydicarbonate, t-butylperoxypivalate, t-butylperoxy-2-ethylhexanoate, and dicumyl peroxide; Persulfate initiators such as potassium persulfate, sodium persulfate, and ammonium persulfate; Redox (oxidation-reduction) such as combinations of the above persulfate initiators with reducing agents such as sodium metabisulfite and sodium bisulfite, systems based on organic peroxides and tertiary amines, and systems based on organic hydroperoxides and transition metals Initiator; Other initiators such as pinacol; And the like (and mixtures thereof). Azo compounds and peroxides are generally preferred. Photoinitiators such as substituted acetophenones such as benzyl dimethyl ketal and 1-hydroxycyclohexyl phenyl ketone; Substituted alpha-ketols such as 2-methyl-2-hydroxypropiophenone; Benzoin ethers such as benzoin methyl ether and benzoin isopropyl ether; Substituted benzoin ethers such as anisoin methyl ether; Aromatic sulfonyl chlorides; Photoactive oxime; And the like (and mixtures thereof) can likewise be used. Other suitable photoinitiators are described in US Pat. No. 6,486,227 (Nohr, et al.) And US Pat. No. 6,780,896 (MacDonald, et al.), Both of which are incorporated herein by reference.

Although not required, additional components may be used inside the crosslinked network to facilitate fixation of the pH indicator. For example, an anchoring compound may be used that connects the pH indicator to the surface of the substrate and further improves the durability of the pH indicator on the substrate. Typically, the fixation compound is larger in size than the pH indicator, thus increasing the chance of remaining on the surface of the substrate during use. For example, macromolecular compounds such as polymers, oligomers, dendrimers, particles, and the like may be mentioned as the fixing compound. The polymer anchoring compound can be natural, synthetic, or a combination thereof.

The manner in which the fixation compound is used to link the pH indicator and the substrate can vary. In one embodiment, for example, the color change composition is applied to the cellulose fibers after the fixing compound is attached to the pH indicator as part of the color change composition. In another embodiment, the discoloration composition can be applied after the fixing compound is bound to the cellulose fibers. In another embodiment, the materials are applied to the substrate as separate components, and the attachment reaction can occur in situ, optionally simultaneously with crosslinking of the network. For example, the pH indicator may bind to the fixation compound, the fixation compound may bind to the substrate, and at the same time a crosslinking reaction may occur between the fixation compounds, between the indicators, or between both. In one such embodiment, the thus formed crosslinked network can be physically immobilized on the porous membrane of the substrate without the need to bond the porous membrane and other components of the system. In particular, the crosslinked network may extend a portion of it into and between the pores of the porous membrane, so that even if no special bond is formed between the substrate and the components of the crosslinked network, it may be physically detained on the substrate.

It will be appreciated that other attachment techniques besides covalent bonds, such as charge-charge interactions, may also be used to attach the fixing compound to the substrate and / or to attach the pH indicator of the discoloration composition to the fixing compound. For example, a charged anchoring compound, such as a positively charged anchoring compound, can be immobilized on the negatively charged substrate via a charge-charge interaction between the two. Similarly, negatively charged indicators can be immobilized on positively charged fixing compounds.

It is important to choose a pH indicator that is sensitive to pH changes caused by urine. Since normal urine pH is from about 5.5 to about 10.5, useful pH indicators may exhibit significant color conversion at less than about 5.5 or more than about 10.5. The pH indicator color conversion pH is preferably about 1.0 to about 5.5 or about 10.5 to about 11.5.

For example, in certain embodiments, phthalein dye sources constitute one class of suitable pH-sensitive dye sources that can be used in the present invention. Exemplary pH indicators include bromophenol blue (3 ', 3 ", 5', 5" -tetrabromophenolsulfonphthalein), bromochlorophenol blue (dibromo-5 ', 5 "-dichlorophenol Sodium salt of sulfonphthalein), bromocresol green (3 ', 3 ", 5', 5" -tetrabromo-ortho-cresolsulfonphthalein), etc. Another suitable phthalein dye source is mentioned. Thymolphthalein exhibits a conversion from colorless to blue in a pH range of about 9.4 to 10.6, and bromophenol blue is yellow in a pH range of about 3.0 to 4.6. To violet, bromocresol green shows a transition from yellow to blue in the pH range of about 3.8 to 5.4.

Anthraquinones constitute another suitable class of pH-sensitive pigment sources used in the present invention. Anthraquinones have the following general structural formula:

The numbers 1 to 8 shown in the general formula indicate the position on the fused ring structure in which the substitution of the functional group may occur. Some examples of functional groups that may be substituted on the fused ring structure include halogen groups (e.g. chlorine or bromine groups), sulfonyl groups (e.g. sulfonic acid salts), alkyl groups, benzyl groups, amino groups (e.g. primary, secondary, tertiary or quaternary Amine), carboxyl group, cyano group, hydroxy group, popularity, etc. are mentioned. Functional groups that provide ionization capabilities are often referred to as "chromophores". Substitution of the ring structure by the chromophore leads to a shift in the absorption wavelength of the compound. Thus, depending on the type of chromophore (eg, hydroxyl, carboxyl, amino, etc.) and the degree of substitution, a wide variety of quinones with various colors and intensities can be formed. Other functional groups, such as sulfonic acids, can also be used to make certain types of compounds (eg high molecular weight anthraquinones) water soluble.

Some suitable anthraquinones that may be used in the present invention include Mordant, Alizarin, and the like. For example, alizarin yellow R shows a transition from yellow to scarlet in the pH range of about 10.1 to 12.0.

Another suitable class of pH-sensitive pigment sources that can be used are aromatic azo compounds having the following general structure:

XR ₁ -N = NR ₂ -Y

Where

R ₁ is an aromatic group,

R ₂ is selected from the group consisting of aliphatic and aromatic groups,

X and Y are independently from the group consisting of hydrogen, halide, -NO ₂ , -NH ₂ , aryl group, alkyl group, alkoxy group, sulfonate group, -SO ₃ H, -OH, -COH, -COOH, halide and the like Is selected. Also suitable are azo derivatives such as azoxy compounds (XR ₁ -N = NO-R ₂ -Y) or hydrazo compounds (XR ₁ -NH-NH-R ₂ -Y). Specific examples of such azo compounds (or derivatives thereof) include methyl violet 2B, methyl yellow, methyl orange, methyl red, and methyl green. For example, methyl violet 2B converts from yellow to violet in a pH range of about 0 to 1.6, methyl yellow converts from red to yellow in a pH range of about 2.9 to 4.0, and methyl orange of about 3.1 to 4.4. Switch from red to yellow in pH range.

Arylmethanes such as diarylmethane and triarylmethane constitute another class of suitable pH-sensitive colorants for use in the present invention. For example, malachite green typically converts from yellow to bluish green in the pH range of 0.2-1.8. At pH above about 1.8, malachite green turns dark green.

Other suitable pH-sensitive colorants that can be used include Congo red, methylene blue, acid fuchsin, indigo carmine, picric acid, methyl yellow, phloxine B, 2,4-dinitrophenol, nile blue A, and the like. Can be. For example, Congo red converts from blue to red in a pH range of about 3.0 to 5.2, and neutral red converts from red to yellow in a pH range of about 11.4 to 13.0.

However, any suitable pH indicator that may be known in the art is contemplated for use in the present invention.

In certain embodiments, the initial color of the immobilized indicator can be readily controlled by immobilizing the indicator with the pH modifier, which is an acid, a buffer, a base, or some combination thereof. Initial color is important to provide sharp color contrast as much as possible. For example, when bromophenol blue is used as the indicator, the acid conditions give yellow to the indicator zone, which is clearly distinguishable from blue at about 5.5 to about 10.5, which is the pH range of normal urine.

Suitable pH adjusting agents include any reagent capable of providing the composition with a pH in the range of less than about 5.5 or greater than about 10.5. In addition, other suitable pH adjusting agents include sulfonic acids such as 2- [N-morpholino] ethane sulfonic acid ("MES"), carboxylic acids, and polymeric acids. Specific examples of suitable carboxylic acids are citric acid. , Glycolic acid, lactic acid, acetic acid, maleic acid, gallic acid, malic acid, succinic acid, glutaric acid, benzoic acid, malonic acid, salicylic acid, gluconic acid, and mixtures thereof. Acrylic acid) and its copolymers (e.g. maleic acid-acrylic acid, sulfonic acid-acrylic acid and styrene-acrylic acid copolymers), crosslinked polyacrylic acid, poly (methacrylic acid) having a molecular weight of less than about 250,000, and carrageic acid, carboxymethyl Natural polymeric acids such as cellulose and alginic acid Likewise, pH adjusters provide an initial pH outside the typical pH range of urine, whereby discoloration may occur in the presence of urine.

The discoloration composition of the present invention also includes a humectant. Surprisingly, it has been found that compositions of cellulose fibers treated with highly positively charged polymers and immobilized with pH indicators and pH regulators are not very good in urine wetting given the highly charged properties of the fibers. The material of the present invention includes a humectant that provides improved urine wetting. Wetting agents are less than about 0.5 weight percent of the total weight of the treated fibers of the substrate, more specifically less than about 0.1 weight percent of the total weight of the treated fibers of the substrate, and even more specifically, about the total weight of the treated fibers of the substrate. It may be present in an amount of less than 0.01% by weight. For example, the discoloration composition may comprise a treatment composition containing a water soluble organic polymer such as polysaccharides and derivatives thereof. The discoloration composition can also use surfactants to improve the hydrophilicity of the fibers. Ionic surfactants (such as anionic, cationic, or amphoteric surfactants) and / or nonionic surfactants can be used in the discoloration composition. Particularly suitable surfactants are nonionic surfactants such as alkyl glycosides, ethoxylated alkylphenols, ethoxylated and propoxylated fatty alcohols, ethylene oxide-propylene oxide block copolymers, fats (C ₈ -C _18). ) Ethoxylated esters of acids, condensation products of ethylene oxide and long chain amines or amides, condensation products of ethylene oxide and alcohols, and mixtures thereof. Various specific examples of suitable nonionic surfactants include methylglucamine access -10 (methyl gluceth-10), PEG-20 methyl glucose distearate, PEG-20 methyl glucose sesquioleate stearate, C _{11 -15} -20 Palace (pareth -20), ceteth-8, cethes-12, dodoxynol-12, laureth-15, PEG-20 castor oil, polysorbate 20 , Steareth-20, polyoxyethylene-10 cetyl ether, polyoxyethylene-10 stearyl ether, polyoxyethylene-20 cetyl ether, polyoxyethylene-10 oleyl ether, polyoxyethylene-20 Oleyl ether, ethoxylated nonylphenol, ethoxylated octylphenol, ethoxylated dodecylphenol, or ethoxylated fatty (C ₆ -C ₂₂ ) alcohols containing 3 to 20 ethylene oxide moieties, polyoxyethylene-20 iso Hexadecyl ether, polyoxyethylene-23 glycerol laurate, polyoxyethylene-20 glycerol Reel stearate, PPG-10 methyl glucose ether, PPG-20 methyl glucose ether, polyoxyethylene-20 sorbitan monoester, polyoxyethylene-80 castor oil, polyoxyethylene-15 tridecyl ether, polyoxyethylene-6 Tridecyl ether, laureth-2, laureth-3, laureth-4, PEG-3 castor oil, PEG 600 dioleate, PEG 400 dioleate, and mixtures thereof.

In certain embodiments, alkyl glycosides are used in the discoloration composition. Alkyl glycosides are generally prepared by reacting a monosaccharide or a compound that can be hydrolyzed to a monosaccharide in an acid medium with an alcohol such as a fatty alcohol. For example, US Pat. Nos. 5,527,892 and 5,770,543, which are incorporated herein by reference in their entirety for all purposes, describe alkyl glycosides and / or methods for their preparation. Examples of suitable alkyl glycosides commercially available are Glucopon ™ 220, 225, 425, 600 and 625, all of which are available from Cognis Corp. (Cincinnati, Ohio). These products are mixtures of alkyl mono- and oligoglucopyranosides with alkyl groups based on fatty alcohols derived from coconut and / or palm kernel oil. Glucopon ™ 220, 225 and 425 are examples of particularly suitable alkyl polyglycosides. Glucopon ™ 220 is an alkyl polyglycoside comprising a mixture of alkyl groups having an average of 1.4 glucosyl residues and 8 and 10 carbons per molecule (average 9.1 carbons per alkyl chain). Glucopon ™ 225 is a related alkyl polyglycoside having a linear alkyl group (an average alkyl chain carbon atom of 9.1) having 8 or 10 carbon atoms in the alkyl chain. Glucopon ™ 425 comprises a mixture of alkyl polyglycosides (average alkyl chain carbon atoms of 10.3) comprising alkyl groups having 8, 10, 12, 14 or 16 carbon atoms each. Glucopon ™ 600 comprises a mixture of alkyl polyglycosides (average alkyl chain carbon atoms of 12.8) comprising alkyl groups having 12, 14 or 16 carbon atoms each. Glucopon ™ 625 comprises a mixture of alkyl polyglycosides (average alkyl chain carbon atoms of 12.8) comprising alkyl groups having 12, 14 or 18 carbon atoms each. Another suitable alkyl glycoside is available from Dow Chemical Co. (Midland, MI) under the name Triton ™ or Tween ™.

Hereinafter, one specific embodiment of the method of detecting the presence of urine will be described in more detail. First, a urine test sample is applied to the substrate. As urine flows through the substrate, a change in hydrogen ion concentration is detected by the pH indicator of the discoloration composition. Thus, the presence of urine can be detected by visually or by measuring the change in color or color intensity.

In certain embodiments, the substrate is configured to discolor in less than about 5 minutes in contact with urine, more specifically in less than about 3 minutes in contact with urine, and even more specifically in less than about 1 minute in contact with urine.

The present invention provides a simple, compact and cost effective material for accurately detecting urine. Test results may be visible to the person performing the test in an immediate manner and easily observed under test conditions that are good for obtaining highly reliable and consistent test results.

In accordance with the present invention, one or more materials described herein may be incorporated into an absorbent article. "Absorbent article" generally refers to any article that can absorb water or other fluids. Examples of some absorbent articles include personal care absorbent articles, such as diapers, training pants, absorbent underwear, incontinence articles, feminine hygiene products (such as sanitary napkins), swimwear, baby wipes, and the like; Medical absorbent articles such as garments, perforated materials, underzones, bedzones, bandages, absorbent drapes, and medical wipes; Restaurant wipes; Cloth supplies; Etc., but is not limited thereto. Materials and methods suitable for the formation of such absorbent articles are well known in the art. Typically, the absorbent article includes a substantially liquid impermeable layer (eg, outer cover), a liquid permeable layer (eg, bodyside liner, surge layer, etc.), and an absorbent core.

Hereinafter, various embodiments of absorbent articles that can be formed in accordance with the present invention will be described in more detail. For illustrative purposes only, the absorbent article is shown as diaper 101 in FIG. 1. In the embodiment shown, the diaper 101 is shown as having an hourglass shape in its unfastened form. However, other shapes, such as generally rectangular shapes, T-shapes, or I-shapes may of course be used. As shown, the diaper 101 includes a chassis formed by various components, including an outer cover 117, a bodyside liner 105, an absorbent core 103, and a surge layer 107. However, it will be appreciated that other layers may be used in the exemplary embodiments of the present invention. Likewise, one or more layers shown in FIG. 1 may also be removed in certain exemplary embodiments of the present invention.

The bodyside liner 105 is generally used to help isolate the wearer's skin from the liquid retained in the absorbent core 103. For example, liner 105 typically provides a bodyside surface that is flexible, soft to the touch, and does not irritate the wearer's skin. Typically, the liner 105 is also less hydrophilic than the absorbent core 103 so that its surface remains relatively dry to the wearer. As noted above, the liner 105 may be liquid permeable such that the liquid can easily pass through its thickness. Exemplary liner structures containing nonwoven webs are described in US Pat. No. 5,192,606 to Proxmire, et al .; 5,702,377 to Collier, IV, et al .; No. 5,931,823 to Stokes, et al .; 6,060,638 to Paul, et al .; And 6,150,002 (Varona), and US Patent Application Publication No. 2004/0102750 (Jameson); 2005/0054255 to Morman, et al .; And 2005/0059941 to Baldwin, et al., All of which are incorporated herein by reference in their entirety for all purposes.

The diaper 101 may also include a surge layer 107 that assists in slowing and diffusing the surge or ejection of liquid that may be rapidly introduced into the absorbent core 103. Preferably, the surge layer 107 quickly receives and temporarily retains liquid and then discharges it into the reservoir or reservoir of the absorbent core 103. In the illustrated embodiment, for example, the surge layer 107 is interposed between the inward surface 116 of the bodyside liner 105 and the absorbent core 103. Alternatively, surge layer 107 may be disposed on outward surface 118 of bodyside liner 105. The surge layer 107 is typically made of a material with high liquid permeability. Examples of suitable surge layers are described in US Pat. Nos. 5,486,166 (Ellis, et al.) And 5,490,846 (Ellis, et al.), Which are incorporated herein by reference in their entirety for all purposes.

Outer cover 117 is typically formed from a material that is substantially impermeable to liquid. For example, the outer cover 117 can be formed from a thin plastic film or other flexible liquid impermeable material. In one embodiment, the outer cover 117 is formed from a polyethylene film having a thickness of about 0.01 millimeters to about 0.05 millimeters. The film may be impermeable to liquids, but permeable to gases and water vapor (ie, "breathable"). This allows vapor to escape from the absorbent core 103 while still preventing liquid discharge through the outer cover 117. If a more cloth-like feel is desired, the outer cover 117 can be formed from a polyolefin film laminated to a nonwoven web. For example, a polypropylene film thinned by stretching may be thermally laminated to a spunbond web of polypropylene fibers.

In addition to the components described above, the diaper 101 may also contain various other components known in the art. For example, the diaper 101 may also contain a substantially hydrophilic tissue wrapsheet (not shown) that assists in maintaining the integrity of the fibrous structure of the absorbent core 103. The tissue wrapsheet is typically disposed around at least the two major surfaces of the absorbent core 103 and consists of an absorbent cellulosic material, such as creped wadding or high wet strength tissue. The tissue wrapsheet may be configured to provide a wicking layer to help disperse the liquid quickly over the absorbent fiber mass of the absorbent core 103. Wrapsheet material on one side of the absorbent fibrous mass can be bonded to a wrapsheet disposed on the opposite side of the fibrous mass to effectively pinch the absorbent core 103. Furthermore, the diaper 101 may also include a ventilation layer (not shown) disposed between the absorbent core 103 and the outer cover 117. If used, the ventilation layer may assist in reducing the dampness of the outer cover 117 by isolating the outer cover 117 from the absorbent core 103. Examples of such ventilating layers may include a nonwoven web laminated to a breathable film such as described in US Pat. No. 6,663,611 (Blaney, et al.), Which is incorporated herein by reference in its entirety for all purposes.

In some embodiments, diaper 101 may also include a pair of side panels (or ears) (not shown) that extend from the side edge 132 of diaper 101 to one side of the waist region. The side panel may be integrally formed with the selected diaper component. For example, the side panels may be integrally formed with the outer cover 117 or from the material used to provide the top surface. In other configurations, the side panels may be provided by members that are connected and assembled to the outer cover 117, the top surface, between the outer cover 117 and the top surface, or in various other configurations. If desired, the side panels can be made elastic or otherwise elastomeric by use of the elastic nonwoven composite of the present invention. Examples of absorbent articles comprising elasticizing side panels and optionally configured fastener tabs are described in PCT patent application WO 95/16425 (Roessler); US Patent No. 5,399,219 to Rosesler et al .; US Patent No. 5,540,796 to Fries; And US Pat. No. 5,595,618 to Fries, each of which is incorporated herein by reference in its entirety for all purposes.

As representatively shown in FIG. 1, the diaper 101 may also include a pair of suppression flaps 112 that are configured to provide a barrier and to limit the lateral flow of body discharge. The containment flap 112 may be disposed adjacent the side edges of the absorbent core 103 along the laterally facing side edges 132 of the bodyside liner 105. The containment flap 112 may extend longitudinally along the entire length of the absorbent core 103 or only partially extend along the length of the absorbent core 103. The containment flap 112 may optionally be disposed anywhere along the side edge 132 of the diaper 101 in the crotch region 110 when the length is shorter than the absorbent core 103. In one embodiment, the inhibition flap 112 extends along the entire length of the absorbent core 103 to better inhibit body discharge. Such suppression flaps 112 are generally well known to those skilled in the art. For example, suitable structures and arrangements for the suppression flap 112 are described in US Pat. No. 4,704,116 to Enloe, which is incorporated herein by reference in its entirety for all purposes.

In order to provide an improved fit and assist in reducing leakage of body discharge, the diaper 101 can be elasticized with a suitable elastic member, as further described below. For example, as representatively shown in FIG. 1, the diaper 101 functionally tightens the side edges of the diaper 101 to fit snugly around the wearer's leg to reduce leakage and provide improved comfort and appearance. Leg elastics 106 configured to provide elasticized leg bands that can be made. In addition, a waist elastic 108 can be used to elasticize the end edge of the diaper 101 to provide an elasticized waistband. The waist elastic 108 is configured to provide a fit that is elastic and comfortable close to the waist of the wearer.

Diaper 101 may also include one or more fasteners 130. For example, in FIG. 1 two flexible fasteners 130 for creating a waist opening around a wearer and a pair of leg openings are shown on opposite side edges of the waist region. The shape of the fastener 130 may vary in general, but may include, for example, a rectangular shape, a square shape, a circle shape, a triangle shape, an ellipse shape, a line shape, and the like. Fasteners include, for example, hook-and-loop materials, buttons, pins, snaps, adhesive tape fasteners, adhesives, fabric-and-loop fasteners, and the like. In one particular embodiment, each fastener 130 comprises a separate piece of hook material, secured to the inner surface of the flexible backing.

The various areas and / or components of the diaper 101 can be assembled together using any known attachment mechanism such as adhesives, ultrasonics, thermal bonds, and the like. Suitable adhesives include, for example, hot melt adhesives, pressure sensitive adhesives and the like. If used, the adhesive may be applied as a uniform layer, patterned layer, sprayed pattern, or any discrete lines, swirls or dots. In the illustrated embodiment, for example, the outer cover 117 and the bodyside liner 105 are assembled to each other and to the absorbent core 103 using an adhesive. Alternatively, the absorbent core 103 may be connected to the outer cover 117 using conventional fasteners such as buttons, hook-and-loop fasteners, adhesive tape fasteners, and the like. Similarly, other diaper components, such as leg elastic member 106, waist elastic member 108, and fastener 130, can also be assembled to form diaper 101 using any attachment mechanism.

Generally speaking, the materials of the present invention may be incorporated into absorbent articles in a variety of different orientations and forms, as long as they can receive urine and provide discoloration to a user or guardian of the detection of urine. The visibility of the material can be obtained in various ways. For example, in some embodiments, the absorbent article is a transparent or translucent portion 140 (eg, window, film, etc.) that allows the material to be easily observed without removing the absorbent article from the wearer and / or disassembling the absorbent article. It may include. In other embodiments, the material may extend through a hole or hole in the absorbent article for viewing. In another embodiment, the material can be simply placed on the surface of the absorbent article for observation.

Regardless of the particular manner in which the material is incorporated, urine may be released directly to a portion of the material 120 or may be released on the components of the absorbent article into which the material 120 is incorporated. After sufficient reaction time, the color can be detected to determine the presence of urine.

The invention can be better understood with reference to the following examples.

Example

Example 1 1 g of dispersed cellulose fiber was combined with 0.5 ml 20% Kymene in 60 ml water. The mixture was heated to 70 ° C. for 2 hours, filtered and washed three times with water. The washed fibers were resuspended in an aqueous solution containing 0.4 mg / ml bromocresol green and 4 mg / ml citric acid for 1 hour. The fibers were then subdivided into three tubes, named tubes 1, 2, and 3, respectively. 0.5 mg / ml Tween-20 was added to tube 2. Tween-20 200 mg / ml was added to tube 3. The fibers in the three tubes were filtered. Three fiber sheets were then dried at 70 ° C. for 1 hour. One small piece of each sheet was cut out and placed on a tissue sheet and 200 μl of synthetic urine was applied to each piece, which was named samples 1, 2, and 3, respectively. Synthetic urine penetrated much faster into the matrix of Samples 2 and 3 than Sample 1, showing better wettability following Tween-20 treatment. Discoloration from yellow / green to blue occurred faster in samples 2 and 3 than in sample 1. However, it was found that for Sample 3 more dye leached from the fibrous sheet into the tissue than for Samples 1 and 2. In general, the wettability enhancer should not exceed 0.5% of the total weight of the treated fibers. Thus, the benefits of better wettability and the negative effects of increased leaching need to be carefully balanced using an appropriate amount of wettability enhancer.

Example 2 20 ml Kymene 0.5 ml, 0.1 ml, and 0.02 ml in each of three tubes containing 600 mg of dispersed cellulose fibers in 40 ml of water (named tubes 1, 2, and 3, respectively) Added. Samples were sonicated in a bath at 50 ° C. for 3 hours, then filtered and washed once with water. The filtered fibers were then dispersed in 40 ml of water. 0.5 ml of bromocresol green (10 mg / ml) was added to each sample and incubated for 1 hour at room temperature. The fibers were filtered off and washed once with water. The filtrate of Sample 1 was almost colorless, indicating that all the dye was absorbed by the fibers. Slight blue was observed in the filtrate of Sample 2. Dark blue was observed in the filtrate of Sample 3, suggesting that large amounts of dye were not absorbed by the fibers. The fibers of samples 1 and 2 were dark blue, while the fibers of sample 3 were light blue. The filtered fibers of each sample were resuspended in 18 ml of water and 2 ml of 40 mg / ml citric acid for half an hour. The fibers of Sample 1 turned pale blue, but the fibers of Samples 2 and 3 became yellowish. Some of the fibers were filtered and dried at 37 ° C. for 1 hour. The fibrous sheets of samples 2 and 3 were yellow while the fibrous sheets of sample 1 were yellowish blue. 100 μl of Hepes buffer (0.1M, pH: 7.2) was applied to each piece of fiber sheet, and all pieces were dark blue in color. However, it took several minutes for the buffer to penetrate the entire fiber sheet, indicating that water wettability is less desirable.

Example 3 : To a portion (20 mL) of Sample 2 from Example 2 was added 2% Triton-X-100, incubated for 30 minutes, filtered and dried at 30 ° C. for 1 hour. 100 ml of Hepes buffer was applied to the piece of fiber sheet and the piece of sample 2 fiber prepared in Example 2. The buffer immediately penetrated the fiber sheet treated with Triton-X-100, while it took several minutes for the buffer to fully penetrate the fiber sheet not treated with Triton-X-100.

Example 4 : A rectangular hole was made near the center of the outer cover by removing part of the outer cover of the Huggies® diaper. Then, the fiber sheet prepared in the above examples was inserted in contact with the absorbent core. Transparent Scotch tape was used to cover the material and secure it against the absorbent core. 10 ml of urine was applied to the medial center. The color of the majority (> 50%) of the fiber pieces prepared as Sample 2 and treated with Tween-200 changed from yellow to blue in less than 5 minutes. Five minutes after the addition of 10 ml of additional urine, almost the entire piece turned from yellow to blue. Only a very small mottled portion (<10%) of the fiber piece prepared as Sample 2 and not treated with Tween-200 changed color from yellow to blue after more than 5 minutes. Less than 30% of the fiber pieces prepared as Sample 2 and not treated with Tween-200 changed color from yellow to blue 30 minutes after the addition of 10 ml of additional urine.

Example 5 20 μl Kymene 200 μl, 100 μl, and 50 μl were added to each of three tubes containing 600 mg of dispersed fibers in 40 ml of water (designated tubes 1, 2, and 3). . The mixture was heated at 80 ° C. for 30 minutes. Each sample was divided into two 20 mL samples. One of them was filtered and washed once with water. To each of the six samples was added 1.5 ml of a mixture containing 2 ml of bromocresol green (10 mg / ml) and 8 ml of citric acid (40 mg / ml) and 2 ml of Triton-X-100 (2%). Samples were incubated for 20 minutes at room temperature. The sample was then filtered and dried at 37 ° C. for 2 hours. Dry fiber sheets made from tubes 1, 2, and 3, which filtered excess Kymene, showed dark blue yellow, blue yellow, and yellow, respectively. The color of the pieces of fiber sheets prepared from these samples turned dark blue upon addition of 200 μl of synthetic urine. Dry fiber sheets made from tubes 1, 2, and 3, which did not remove excess Kymene, all displayed very bright white / blue. Very few dyes were absorbed into the fibers. The color of the pieces of fiber sheets prepared from these samples did not discolor upon addition of 200 μl of synthetic urine.

For simplicity and clarity, all numerical ranges described herein are to be understood as a description supporting the claims referring to all subranges ending in integer values within the specified range. As a fictitious illustrative example, the description in the range of 1 to 5 herein includes 1 to 4; 1 to 3; 1 to 2; 2 to 5; 2 and 4; 2 to 3; 3 to 5; 3 and 4; And claims for all of the sub-ranges of 4 to 5.

Those skilled in the art can make these and other variations and modifications to the invention without departing from the spirit and scope of the invention as described in more detail in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those skilled in the art will recognize that the above description is for illustrative purposes only and is not intended to limit the content further described in the appended claims.

Claims (20)

Contacting urine with a substrate comprising charged cellulose fibers having a discoloring composition comprising a pH indicator, a pH adjuster, and a wetting agent configured to discolor upon contact with urine; And
determining the presence of urine based on discoloration of the pH indicator
Urine detection method comprising a. The method of claim 1 wherein the pH indicator is bromochlorophenol blue, bromophenol blue, methyl orange, methyl yellow, alizarin yellow GG, bromocresol green, phloxine B, Congo red, ethyl orange, nile blue A, aniline Blue WS, or a combination thereof. The method of claim 1 wherein the cellulose fibers are charged with a positively charged polyamide epichlorohydrin polymer. The method of claim 1 wherein the pH adjusting agent comprises an inorganic acid, an organic acid, a polymeric acid, or a combination thereof. The method of claim 1 wherein the pH adjusting agent comprises an organic acid comprising oxalic acid, citric acid, salicylic acid, tartaric acid, or a combination thereof. The method of claim 1 wherein the pH adjusting agent comprises an inorganic base, an organic base, or a combination thereof. The method of claim 1 wherein the humectant comprises a nonionic surfactant. The method of claim 1 wherein the humectant is present in an amount of less than about 0.5 weight percent of the substrate. The method of claim 1 wherein the humectant is present in an amount of less than about 0.1% by weight of the substrate. The method of claim 1 wherein the humectant is present in an amount of less than about 0.01% by weight of the substrate. The method of claim 1, wherein the substrate is configured to discolor in less than about 5 minutes upon contact with urine. The method of claim 1, wherein the substrate is configured to discolor in less than about 1 minute upon contact with urine. A substantially liquid impermeable layer;
Liquid permeable layer;
An absorbent core positioned between the substantially liquid impermeable layer and the liquid permeable layer; And
Charged cellulosic fibers incorporated in the article and positioned to be in fluid communication with the urine generated by the wearer of the article, wherein the discoloration composition comprises a pH indicator, a pH regulator, and a wetting agent configured to discolor upon contact with urine.
An absorbent article, comprising: determining the presence of urine. The method of claim 13 wherein the pH indicator is bromochlorophenol blue, bromophenol blue, methyl orange, methyl yellow, alizarin yellow GG, bromocresol green, phloxine B, Congo red, ethyl orange, nile blue A, aniline An absorbent article comprising blue WS, or a combination thereof. The absorbent article of claim 13 wherein the cellulose fibers are charged with a positively charged polyamide epichlorohydrin polymer. The absorbent article of claim 13 wherein the pH adjusting agent comprises an inorganic acid, an organic acid, a polymeric acid, or a combination thereof. The absorbent article of claim 13 wherein the pH adjusting agent comprises an inorganic base, an organic base, or a combination thereof. The absorbent article of claim 13 wherein the humectant comprises a nonionic surfactant. The absorbent article of claim 13 wherein the humectant is present in an amount of less than about 0.5% by weight of the charged cellulose fibers. The absorbent article of claim 13 having a window capable of viewing at least a portion of the charged cellulose fibers.

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